I have 2017 Michelins on the old Benz that I just drove cross-country in 110 deg. heat in places, they are still fine. First 5 years or so were in WA. state, so not much heat or UVs, which can drastically shorten safe life span. I think that the 10 year rule mentioned above is solid advice. Driving on public roads on 18 year old tires is crazy...what if you hit someone because you could not stop in time?
